netdev - Re: [iproute PATCH] tc: u32: Fix key folding in sample option

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Message-ID: <0cab775c-cd3c-f3a0-7680-570cc92eb96e@mojatatu.com>
Date:   Thu, 4 Feb 2021 09:34:01 -0500
From:   Jamal Hadi Salim <jhs@...atatu.com>
To:     Phil Sutter <phil@....cc>,
        Stephen Hemminger <stephen@...workplumber.org>,
        netdev@...r.kernel.org
Subject: Re: [iproute PATCH] tc: u32: Fix key folding in sample option

On 2021-02-04 9:04 a.m., Phil Sutter wrote:
> Jamal,
> 
> On Thu, Feb 04, 2021 at 08:19:55AM -0500, Jamal Hadi Salim wrote:
>> I couldnt tell by inspection if what used to work before continues to.
>> In particular the kernel version does consider the divisor when folding.
> 
> That's correct. And so does tc. What's the matter?
> 

tc assumes 256 when undefined. Maybe man page needs to be
updated to state we need divisor specified otherwise default
is 256.

>> Two examples that currently work, if you can try them:
> 
> Both lack information about the used hashkey and divisor.
> 
>> Most used scheme:
>> ---
>> tc filter add dev $DEV parent 999:0  protocol ip prio 10 u32 \
>> ht 2:: \
>> sample ip protocol 1 0xff match ip src 1.2.3.4/32 flowid 1:10 \
>> action ok
>> ----
> 
> htid before: 0x201000
> htid after: 0x201000
> 

Ok, this is the most common use-case. So we are good.

Acked-by: Jamal Hadi Salim <jhs@...atatu.com>


cheers,
jamal